Air compressor engine



J. R. FRANTZ 1,970,371

AIR COMPRESSOR ENGINE Original Filed June 27, 19 8 2 Sheets-Sheet l Ihwentor a! A X M,mmm-

(Ittofnegs AIR COMPRESSOR ENGINE Original Filed June 2?, i928 2 Sheets-Sheet 2 3nventor an M M MW

' (Ittornegs Patented Aug. 14, 1934 AIR COMPRESSOR ENGINE of Wisconsin Continuation of application Serial No; 288,564, 1

June 27, 1928.

This application 1932, Serial No. 631,786

September 6,

3 Claims. (01. 123-129)v This invention relates to improvements in air compressor engines.

The present application is a continuation of application Serial No. 288,564 filed June 27, 1928.

It is the object of the invention to overcome, without interference with standardization of engine parts, the difliculties inherent in the means heretofore employed for building up auxiliary supplies of compressed air, such as are required incidentally to the operation of locomotives, derricks, hoists, excavators and the like, for which power is furnished byinternal combustion engines.

It is my purpose to eliminate extraneous air compressor units with their attendant difficulties in the way of separate lubrication, driving equip ment, the danger of exposed moving parts, and the inconvenience of any unit which is added as an afterthought and for which there is no adequate place in'the installation. It is equally my purpose to eliminate the extra size, weight, and expense involved in extending the crank shaft of the engine and building an air compressor unit at the end thereof. It is my further purpose to reduce strains on the crank shaft by driving the piston of my improved air compressor from an intermediate point of the engine crank shaft, thereby reducingthe torque required to-be communicated from one end of the shaft to the other.

In certain designs of internal combustion engines which have been widely used there is no central crank shaft bearing and the timing employed is such that the central part of the crankshaft comprises a double crank'operatingthe pistons in two adjacent cylinders. Specifically stated, it is the purpose of the present invention to utilize for the operation of an air compressor piston that portion of such a double crank which lies'between the portions to which the connecting rods leading to the pistons of the intermediate engine cylinders are attached.

In the drawings:

Figure 1 is a side elevation of an internal combustion engine constructed to embody integrally an air compressor in accordance with the invention, the crank case being broken away to expose the crank shaft, crank shaft bearings, and the special air compressor cylinder and connecting rod.

Figure 2 is a transverse section on an enlarged scale through the engine crank case in the plane of the axis of the compressor cylinder.

Like parts are identified by similar reference numerals throughout the several views.

The general construction of the engineshown in the drawings corresponds to the usual practice. The cylinders are provided in pairs in blocks 5, 6, and 7 which are attached to the crank case 8. The crank case is designed to provide bearings at 9, 10, 11, and 12 for the crank shaft 15 which is provided at 16 with a fly-wheel and at 17 with timing gearing.

Since this engine is provided with six cylinders and the crank shaft is of the well known four bearing type, it will be obvious that there'are-two engine connecting rods secured to cranks ofthe crank shaft between each pair ofbearings. Connecting rods 18 and 19 are connected to pistonsin the first two cylinders of the engine and are provided with bearings upon portions of the crank shaft which are 120 divergent and are connected by the crank throw member 20. Similarly connecting rods 21 and 22 operate pistons in thelast two cylinders of the engine and'are provided with bearingson portions of the crank shaft which are 120 divergent and are connected by crank throw member 23.

As has been suggested above, the connecting rods 24 and 25 for the central pair of cylinders are provided with bearings upon a common crank pin portion of the crank shaft which is divergent by 120 from the crank pins which operate connecting rods 18 and 22 on the one hand, and 19 and 21 on the other hand. Thefact that a single crank pin element serves both of these connecting rods makes it unnecessary to employ any crank throw member such as or 23 therebetween, and the fact that the four bearing principle is used in the engine leaves the space between connecting rods 24 and 25 available for the purposes of this invention. 3 I

In order to provide conveniently for the 'cor'n pressor cylinder, I form at a bevele'd'face-on the crankcase 8 to which the compressor cylinder 31 is bolted, as shown in Fig. 2. Such cylinder is preferably jacketed at 32 to carry off the heat of compression. Any approved form of inlet and'exhaust' valves 33and 34 are provided-for the compressor cylinder.

35 is the compressor piston which operates in cylinder 31 in the usual way,being actuated by a connecting rod 36 which, in accordance with this invention, is provided with a bearing upon the same crank pin portion of crank shaft 15 to which connecting rods 24 and 25 are attached. The bearing portion of connecting rod 36 may have its end faces in thrust bearing relation to the other connecting rod bearings and thus may serve as a spacer for such bearings.

For best results the metal of the crank throw members of crank shaft 15 is thickened or squared up or otherwise counterweighted as suggested by the corners illustrated in Fig. 3, whereby to counterbalance the shaft in opposition to the load imposed thereon by connecting rod 36 and its associated compressor piston 35. The counterweighting is preferably such as to give dynamic as well as static crank shaft balance.

In operation, such driving force as is derived from connecting rods 24 and 25 will be imparted to compressor connecting rod 36 with substantially no torque imposed ion-the crank shaft, all of these connecting rods being mounted on the same crank. In no event is the power applied to the compressor required toftraverse more than one half of the length of the crank shaft, thus minimizing the load requirements which would otherwise be imposed on the crank shaft if the power to be transmitted therethrough had to be supplemented by such power as might be required to actuate acompressor located beyond one end of the engine.

, It is important to note that through this arrangement it is possible to add an air compressor to anengine through a change in the crank case and crank shaft only. The addition of the compressor does not alter or affect standardization of any of the engine parts which may require replacementsuchas connecting rods, pistons, or the like.- In fact, the number of parts required for the combination engine and compressor herein disclosed is considerably reduced below the number of parts required for devices heretofore available.

It is also particularly to be noted that extraneous coupling mechanism is wholly avoided, mechanical losses are reduced to a minimum, the space required is substantially that of the engine alone andlubrication of the compressor is effected from the crank case of the engine in whatever manner the engine itself is lubricated. The compressor cylinder is just as available for splash lubrication as are the cylinders of the engine and the compressor connecting rod, being driven from the engine crank shaft, may be lubricated by forced feed through the crank shaft if forced feed .lubricationis employed for the engine.

It will be obvious that the particular angle of disposition of the compressor cylinder is not essential to the invention, the specific arrangement being a matter of choice or mechanical expediency. The primary consideration in the presentinvention is regarded as the operation of the compressor piston from that crank pin por tion which is left available at approximately the exactcenterof the crank shaft due to the absence of crank throw elements and bearings at this point.-

I claim:

1'. In an internal combustion engine, the combination of a series ofsix engine cylinders arranged with their'centers vertical in a common plane and spaced to be normally closely adjacent one another, pistons in said cylinders, connecting rods receiving motion from said pistons, a crank case, main bearings including two central bearings, a crank shaft journaled in said main bearings and provided with five crank portions for said connecting rods including a single crank portion for the connecting rods of the two adjacent central cylinders and positioned between said central main bearings, bearings spaced apart on said single crank portion for the last mentioned connecting rods, a pump cylinder fixed with said crank case for the center thereof to be oifset from said planeand at a substantial angle with respect thereto, and providing inlet and outlet means independent of said engine cylinders, a

piston reciprocable in said pump cylinder, and a connecting rod delivering motion to said pump piston and deriving motion from said single crank portion and between and independently of the ccnnecting rods of said adjacent central engine cylinders.

2. In an internal combustion engine, the combination of a series of six engine cylinders arranged with their centers vertical in a common plane and spaced to be normally closely adjacent one another, pistons in said cylinders, connecting rods receiving motion from saidpistons, a'crank case, main bearings including two central bear-- ings, a crank shaft journaled in said main bearings and provided with bearings for said connecting rods including bearings for the connecting rods of the two adjacent central cylinders and spaced apart between said central main bearings, a pump cylinder fixed with said crank case for the center thereof to be offset from said plane and at a substantial angle withrespect thereto and providing inlet and outlet means independent of said engine cylinders, a piston reciprocable in said pump cylinder, and a connecting rod deliveringv motion to said pump piston and deriving motion from said. crank shaft between and independently of the connecting rods of said adjacent central cylinders.

3. In an internal combustion engine, the combination of a series of enginecylinders arranged with the centers in a common plane-and spaced to be normally closely adjacent one another, pistons in said cylinders, connecting rods receiving motion from said pistons, a crank case, a crank shaft provided with bearings for said connecting rods including two bearings spaced apar-t for the connecting rods of two adjacent cylinders, a pump cylinder fixed with said crank case for the center thereof to be offset from said plane and at a substantial angle withrespect thereto,

whereby said pump cylinder does not increase the on u, 

